The present invention is directed to multi-level stacking containers of the type employed typically to transport and deliver bakery products. The invention is particularly concerned with a container so constructed that like containers may be stacked at either a high or a low elevation upon an underlying container as required by the height of the product contained in the lower container.
There are many examples of multi-level stacking containers in the prior art in which two-level stacking is achieved by orienting the upper of two containers into one orientation relative to the lower container to stack at one level and achieving the other level of stacking by shifting the orientation of the upper container 90.degree. or 180.degree. relative to the underlying container. Typically, this is accomplished by having raised and lowered portions on each of two opposed end walls with the raised and lowered portions on one end wall being laterally off-set from those on the other so that when like end walls are stacked upon each other, a first level of stacking is achieved; and when the upper container is reversed by 180.degree. so that unlike end walls are stacked upon each other, a second level of stacking is achieved. In another frequently employed arrangement, two opposed end walls are of a first height and two opposed sidewalls are of a reduced height. In this arrangement, when the end walls are stacked one upon the other, the containers are in a high stacked relationship; while when the upper container is stacked crossways on the lower container, its bottom rests upon the reduced-height sidewalls to achieve a low stacked relationship. Both of these arrangements typically employ a container with a rectangular bottom.
A prior art container embodying both of these stacking arrangements referred to above (to achieve a three-level stacking container) is disclosed in U.S. Pat. No. 4,402,408; see also U.S. Pat. No. 4,334,616. In either of these prior art examples, it will be noted that when the containers are stacked at either of their two higher levels, which would be the case when the containers are filled with products, the upper of two containers is supported upon the underlying container only along two end walls which means that the bottom container of the stack must support the weight of the entire stack on its two end walls.
U.S. Pat. No. 3,937,327 discloses a container having a square bottom with sidewalls formed with webs having alternately inclined sections interconnected at their upper and lower ends as a series of connected upright or inverted V-shaped patterns. The V-shaped patterns differ for each of the four sides of the container and different stacking levels are achieved by different orientations of the upper container relative to the lower. However, stacking to a desired level requires a careful comparison of the sides of the two containers in order to determine the orientation which will achieve the desired stacking level.
The present invention is directed to a container designed for two-level stacking in which high level stacking is achieved in either of two orientations 180.degree. from each other and in which low level stacking is achieved in either of two orientations 90.degree. from either of the high level stacking orientations. The containers further are supported on all four walls by relatively long support surfaces at either stacking level.